// Copyright (C) 2019-2020 Zilliz. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance
// with the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software distributed under the License
// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
// or implied. See the License for the specific language governing permissions and limitations under the License

#pragma once

#ifdef __linux__

#include <marisa.h>
#include "index/StringIndex.h"
#include <string>
#include <vector>
#include <map>
#include <memory>

namespace milvus::scalar {

class StringIndexMarisa : public StringIndex {
 public:
    StringIndexMarisa() = default;

    int64_t
    Size() override;

    BinarySet
    Serialize(const Config& config) override;

    void
    Load(const BinarySet& set) override;

    void
    Build(size_t n, const std::string* values) override;

    const TargetBitmapPtr
    In(size_t n, const std::string* values) override;

    const TargetBitmapPtr
    NotIn(size_t n, const std::string* values) override;

    const TargetBitmapPtr
    Range(std::string value, OperatorType op) override;

    const TargetBitmapPtr
    Range(std::string lower_bound_value, bool lb_inclusive, std::string upper_bound_value, bool ub_inclusive) override;

    const TargetBitmapPtr
    PrefixMatch(std::string prefix) override;

 private:
    void
    fill_str_ids(size_t n, const std::string* values);

    void
    fill_offsets();

    // get str_id by str, if str not found, -1 was returned.
    size_t
    lookup(const std::string& str);

    std::vector<size_t>
    prefix_match(const std::string& prefix);

 private:
    marisa::Trie trie_;
    std::vector<size_t> str_ids_;  // used to retrieve.
    std::map<size_t, std::vector<size_t>> str_ids_to_offsets_;
    bool built_ = false;
};

using StringIndexMarisaPtr = std::unique_ptr<StringIndexMarisa>;

inline StringIndexPtr
CreateStringIndexMarisa() {
    return std::make_unique<StringIndexMarisa>();
}

}  // namespace milvus::scalar

#endif
